Degree Type
Honors Capstone Project
Date of Submission
Spring 5-1-2006
Capstone Advisor
Dr. Thomas Fondy
Honors Reader
Dr. John Belote
Capstone Major
Biology
Capstone College
Arts and Science
Audio/Visual Component
no
Capstone Prize Winner
no
Won Capstone Funding
no
Honors Categories
Social Sciences
Subject Categories
Biology
Abstract
Multinucleation occurs in neoplastic cells that have been treated with cytochalasin B, a fungal toxin that disrupts actin microfilament structures. When the actin cytoskeleton is disrupted, contractile ring formation and cytokinesis are inhibited. In normal cells cytochalasin B prevents the cells from entering the cell cycle. However in neoplastic cells, since cytokinesis no longer occurs, the dividing cell becomes enlarged and heavily multinucleated. We propose that enlarged leukemia cells may be more sensitive to ultrasound treatment because of their increased size and weakened cytoskeletal structure. To determine the differential chemical and physical response of enlarged, multinucleated cells in comparison with non-enlarged mononucleated leukemia cells, physical separation of the large and small cells is needed. Using 19 μ steel mesh, a filter system was devised to separate enlarged cells greater than 19 μ in diameter from normal leukemia cells with diameters of 15 μ by settling through a 3.5 cm diameter 19 μ stainless steel mesh sieve with no hydrostatic head and no fluid flow through the filter. The distribution of cells sizes was determined with a Coulter Counter, and the viability was determined by hemocytometer counts, re-growth assays, and cloning assays in agarose. We used the purified cells from this experiment to test the cells’ susceptibility to damage by ultrasound. Acoustic cavitation produced by ultrasound is the process by which high intensity acoustic fields in liquids lead to the creation and oscillation of cavities or gas bubbles. Previous research has shown that ultrasound can transiently disrupt cell membranes and, thereby, facilitate the loading of drugs and genes into viable cells without killing the cells. In our experiments, rather, we sought to determine whether there was a sonic sensitivity in cells treated with cytochalasin B that can lead to cell disruption and cell death, which might be exploitable as a potential modality in leukemia therapy. By exposing both CBtreated and control U937 leukemia cells to ultrasound, we have found that at greater lengths of sonic exposure, the CB-treated cells are more damaged than the control cells. Furthermore, we found that there was a statistically significant retardation in growth rate of sonicated CB-treated cells two and six days post-sonication. This same response to the ultrasound was not seen in the control cells. This physical treatment may be applicable to enhancing the cytotoxic effects of microfilament agents in treatment of leukemia in pre-clinical animal models, and may introduce ultrasound as a physical modality in leukemia treatment
Recommended Citation
Gold, Kathryn, "Preparation and Purification of Enlarged Multinucleated U937 Human Leukemia Cells and their Susceptibility to Physical Damage by Ultrasound" (2006). Renée Crown University Honors Thesis Projects - All. 640.
https://surface.syr.edu/honors_capstone/640
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